Linked Life Data

148462

Source:http://linkedlifedata.com/resource/pubmed/id/148462

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
1978-7-24
pubmed:abstractText
An adenine analog 8-[m-(m-fluorosulfonylbenzamido)benzylthio]adenine (FSB-adenine) reacts covalently with sheep heart phosphofructokinase. Under conditions optimal for allosteric kinetics the modified enzyme is less sensitive to inhibition by ATP and insensitive to activation by AMP, cyclic AMP, and ADP. The concentration of fructose-6-P necessary for half-maximal activity is markedly decreased, while the cooperativity to the same substrate is not changed under the same conditions. The modified enzyme is more stable at pH 6.5 when compared with the native enzyme. Changes in the allosteric kinetics of the enzyme are proportional to the extent of modification reaching maximal effect when 3.2 mol of the reagent were bound/mol of tetrameric enzyme. Affinity labeling of the enzyme by the adenine derivative does not affect significantly the catalytic site. This is evidenced by the demonstration that under assay conditions optimal for Michaelian kinetics neither the Km for ATP nor for fructose-6-P is significantly changed following chemical modification. Maximal activity of the modified enzyme was 60% of the native enzyme. ADP gives the best protection, while AMP gives less protection against modification by the reagent. ATP slows the rate of the reaction and causes a slight decrease in maximum binding of the reagent to the enzyme. Modification of the enzyme caused a marked reduction of AMP and ADP binding. The evidence indicates that the modified site is a nucleotide mono- and diphosphate activation site.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
25
pubmed:volume
253
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
3628-34
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1978
pubmed:articleTitle
Heart phosphofructokinase. Allosteric kinetics following affinity labeling modification of the enzyme by 8-[m-(m-fluorosulfonylbenzamido) benzylthio] adenine.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.